Filter



S. W. BRIGGS Nov. 16, 1948,

FILTER Filed Aug. 12, 19

FIQZ.

FIG. I.

JIM/UM 4 Soumwmn W BRlGGS. MW 7% 1 0 Gum/ne Patented Nov. 16, 1948 UiTED STATES PATENT OFFICE",

Southwlck w. Briggs. Washington, 0. c. Application August 12, 1944, Serial No. 549,242

6 Claims. 210-187) 2 I 4 This invention relates to filtration, and more serve to confine the flow so that the fiuid is obliged particularly has reference to afiltering device emto pass through the filter mass. In the specific ploying a filtering material that is adapted to cone tract and expand over a course'of operation. is of cylindrical shape and is so arranged with It is well known that certain materials used as 5 its associated structure that the fiuid passes rafiltration media, particularly cellulosie filtration dially through the cylinder wall. This cylinmaterials, have a tendency to shrink after a pe drical body is held between end plates and strucmoisture. The material may be in'varlous forms, than through the cylinder wall. One of said end such as loose particles, a plurality of elements, or plates (herein called a floating plate") is adapted a single unitary mass, and while the form may to move axially with the cylinder upon expansion vary the degree of shrinkage, all forms are suband contraction of the latter and is provided with ject to some contraction, particularly under cera fluid seal to prevent by-passing of fiuid around tain operating conditions. the cylinder.

The shrinkage does not appreciably vary the In the accompanying drawings, there are disfiltering efiiciency of the material per se, but in closed two specific embodiments of my inv ntion around the filtering mass In general this results n pp i a on in other types of filters. where the filtering mass is a relatively unitary In these drawings:

body and in normal operation is in close and l i Figure 1 is a vertical cross-sectional view of a tight engagement with a casing, t or other filter which includes the present invention.

impervious holder for the filter mass. This can Fi ure 2 is a fragmentary detail d h w f best be appreciated by the reference to the drawthe float ng plate shown in Figure 1, provided jng winch 1 be hereinafter made, with a, fiuid seal between the plate and the cen- In general, the primary object of my invention tube the refill.

is to provide means cooperating with a filter mass Figure 3 is a detailed fragmentary ew n mudsubject to shrinkage to prevent by-pas-s of the ificafion of Figure 1 and Showing the use Of a fluid around the filter mass when such shrinkage floating plate with the fiuid seal associated with occurs. 80

Another object of this invention is to provide a The filter Shown n igure 1 is of generally container or holder for a shrinkable filter mass conventional construction and is adapted for the mass may shrink or expand eraflon. 1011 01] Picks up in Various Ways ap Yet another bject of this invention is to preciable traces of moisture and, as heretofore vide means to prevent by-passing of a filter mass minted the Presence f moisture in e 011 is when the latter shrinks and which at the same apt to cause shrinkage of h lt ring medium. time will not impair the filtering efilciency of the particularly if the latter is of a cellulosic-nature,

mass 40 such as a mass of loose fibers, paper, o a mold d Still another object of this invention is to procellulosic blockvide a plate engageable with one side of a filter Refeljrmg' particularly to i ure 1. the filter providing a seal between the plate and the mass forming a mp. and a removable cover 3. This of a h lder for a filte ma which is adapt t communication with the discharge tube 5 is an maintain tight engagement with the mass notassembly center tube 6 provided with apertures 1. withstanding shrinkage and expansion of such The center tube 6 is provided with an interiorly mass. While not confined thereto, the concept threaded bushing 8 welded therein, into which is finds particular application in connection with a threaded a cover screw 9. A by-pass valve desigcated at25 in'Flgure 2, or

' for a free flow of oil from the which the dirty oil would be able to order to compress mam so that in the event of plugging of the filter cartridge the lubricating system will not be robbed of its required oil. Surrounding the cover screw 9 is g i2 which bears against an assembly to plate i3 to urge the latter downwardly when the cover 3 is secured upon the casing. Mounted upon the center tube 8 is an assembly bottom plate ll. A clean-out plug i5 is provided in the base of the casing for the removal of sediment and sludge.

Intermediate the assembly top and bottom plates i3 and is a. cartridge; designated gener-- ally IS. The cartridge becomes clogged with impurities after a, period of operation and has to be replaced from time to time, hence it is generally called a "refill." This cartridge includes a refill center tube H which is rovided with apertures i8. The apertures are surrounded by a coil spring i3 over which is positioned a wire netting or woven fabric 2| to prevent the entrance into holes l8 of any foreign material, and specifically any particles of the filtering material that may be dislodged from the filtering mass. In certain instances the tube l1 may take the form of a screen or perforated tube with holes throughout itsentire length. Fixedly mounted at the base of the .tube I1 is a refill base plate 22 and at its upper end a refill top plate 23. The base and top plates are provided with suitable gaskets 24 to maintain an oil-tight seal with the assembly top and base plates l3 and I8, and spring i2 possesses sufiicient tension to insure such a tight fit.

Intermediate the refill base and top plates is a filtering mass designated generally 25, which is usually of cylindrical shape, and will be referred to herein as the cylinder. This filtering cylinder maybe formed as a unitary block, such as indiit may be composed of a plurality of superimposed discs 21, as shown in Figure 1. Particularly when a refill center tube is provided with merely holes at its base, as in the case of "Figure 1, the inner periphery of the cylinderv should be spaced from the refill center tube l1, and in this connection it will be noted that therefill center tube I1 is in turn spaced from the assembly center tube 8, thus providing filterin material into the discharge tube 5.

Upon shrinkage of filtering material in the cylinder'25, it is obvious that the cylinder would tend to retractfrom the refill base or upper plates 22 or 23, usually thevlatter. In such event there wouldbe aspace provided between the top of the cylinder 25.,and the refill top plate 23 through pass and then lubricating system through holes I8 unfi tered returnto the and ;11to'=.th,e discharge tube 5 in an condition. f

It will be noted, however, that in the present invention there is provided the floating plate 28 which is; interposed between the top of the cylinder 25 and the underside of the refill top plate 23. In-the normal or expanded condition of cylinder 25 the floating-plate 28 is securely clamped between the cylinder and top plate 23 so that no oil by-passes between the floating plate and the cylinder. I --It might be pointed out that in assembling the refill, the cylinder 25, whether composed of a block or a series of stacked discs, may be arranged around the refill center tube II to rest upon bot tom plate 22,. the floating plate 28 and refill top plate 23 'applied to the top of the cylinder, and then'pressure is exerted upon the assembly in the cylinder 25 to the desired extent, whereupon the center tube I1 is spun plate 28,

about the refill top plate 28 to secure the various elements in assembled relationship. The pressure exerted is sufficient to insure the proper compression of the cylinder 25 and to secure an oiltight fit of the cylinder and plates, and also is ordinarily of such extent as to permit a certain amount of inherent shrinkage of the filtering material without any of the joints being opened. However, when the shrinkage is of an extent to vary the effective length of the cylinderfthe fioating plate 28 moves and maintains a fluid-tight fit with the end of the cylinder, preventing by-pass of the oil therebetween. l

The floating plate 23 is provided with an oil seal designated generally 28, and, as best shown in Figure 2, the oil seal is composed of a neoprene ring 3| and a retaining plate 32. In this connection it will be noted that the inner periphery of the cylinder 25 may be shouldered in order to receive the retaining plate 32. While neoprene has been found to be a particularly eflicacious material for the oil seal, it will be appreciated that any other suitable material that is oil and water resistant, and does not interfere with movement of the floating plate 28 upon the center tube l1, may be substituted.

In the device shown in Figure l, a coil spring 33 is hooked to floating plate 28, or particularly the retaining plate 32. and is anchored at its opposite end to a spring retaining collar 34 located on the refill center tube adjacent the upper end of the screen or fabric 2|. Three or more of such springs 33 are provided and thereby serve to center the cylinder 25 and to maintain it evenly spaced from the center tube i1. These springs also maintain a certain tension upon floating and are suiflcient to insure that the floating plate starts to slide upon the center tube of the end of the cylinder 25 away from the refill top plate 23. Likewise,

' in the event that the refill should be inserted in casing. Any film is,

the filter upside down, the springs 33 have a sufilcient tension tosuspend the cylinder and to maintain the floating plate in contact with the adjacent cylinder end upon shrinkage.

While Figures 1 and 3 show springs 33 and 33A, and while some sort of spring tension is usually preferable for commercial installations, springs are not essential and forms of my invention have been made up which did not employ springs and were found to be entirely satisfactory. It will also be noted that Figure 2 of the drawings omits a spring arrangement; In this connection, it should be pointed out that, notwithstanding compression of the cylinder 25 and the tight fits of refill top plate 23 andfioating plate 28, initial shrinkage of cylinder 25 permits at least a thin film of oil to enter between the refill top plate and the floating plate. -As a matter of fact, in assembling the refill, the top of floating plate 29 and the underside of top plate 23, or both, are usually coated with oil to prevent rust and sticking of the two members. and in such event the film of oil above referred to is initially provided in the refill even before insertion in the filter of course, subject to the same pressure as the'body of oil within the filter casing. This pressure serves to maintain the fioating plate firmly seated upon the top of the cylinder 25 in an oil-tight fit, and as the cylinder retracts such pressure forces the top plate downwardly along with the retracting end.

It is to be noted that as the pressure of oil within the filter casing increases, the force exerted upon floating plate 28 will be correspondingly increased, and this in turn will tend to compress the cylinder 25 and thus reduce its porosity. To this extent the invention tends to compensate for variations in pressure 01' the oil within the casing. and to thus insure unlfor n filtration over periods of variable oil pressure. Inasmuch as shortening or contraction of the cylinder 25 is the result of increased oil pressure, as well as inherent shrinkage of the material per se, the cylinder 25 in actual operation will be shortened and extended with variations in the oil pressure. These variations may be of considerable magnitude, and are visually observable with fluctuations in the pressure of the oil charge.

As heretofore pointed out, the sealing ring 3| is of such construction as not to impede movement of the floating plate 28 upon the center tube l1, and likewise springs 33, if used, should not be of such tension as to interfere with such sliding movement. It will be noted however, thatregardless of the position of floating plate 28, it is impossible for oil to by-pass between the fioating plate and the refill top plate and thence down to discharge apertures I8 in the center tube H. In other words, all of the flow of oil will be confined and directed through the cylinder 25, and consequently all of the oil will be effectively filtered.

As previously pointed out, the filter of Figure 1 is designed for flow of oil from the outside of cylinder 25 radially into the central bore of the cylinder, and in such case the floating plate is preferably slidably sealed to the refill center tube ll. However, the floating plate 28 may be sealed with respect to an enclosing casing or skirt, and this arrangement is preferable particularly in the case of an inside-outside flow.

In Figure 3 there is shown the invention as embodied in a structure in which the refill top plate 23A is provided with a dependingskirt 35. This skirt should be of a length somewhat greater than the maximum amount of shrinkage of the 'cylinder 25, so that regardless of the extent of movement of the floating plate it will at all times be confined within the skirt. In Figure 3 the floating plate 28A is of generally similar construction to the floating plate of Figure 1, and is designed to normally rest between the refill top plate 23A and the cylinder 25A. It will be noted, however, that the oil seal 29A is located at the outer periphery of the floating'plate and slidably engages the skirt 35. This oil seal, as in the case of Figure 1, comprises a neoprene ring 3|A and a retaining plate 32A, the retaining plate extending the whole length of the floating plate 28A and to a point short of the refill center tube HA.

The device shown in Figure 3 is adapted for inside-outside flow, and consequently the retaining plate 32A has a central opening sufficiently large to permit at all times a free passage oi. oil between the center tube HA and its inner periphery. In this way the unfiltered oil is free to enter the space between the refill top plate 23A and the floating plate 28A when the cylinder contracts, and therefore the pressure of the oil charge is at all times exerted upon the top of floating plate 28A.

The floating plate 28A functions in the same manner as floating plate 28 of Figure 1. In other wordsythe spring 33A will cause the floating plate 28A to initially follow the shrinkage of the cylinder, and the pressure of the oil charge upon the top of floating plate 28A will force the floating plate into close and oil-tight engagement with the top of the cylinder, while oil seal 29A will prevent any by-pass oi the unfiltered oil between the fioating plate and the skirt 35.

While Figure 3 discloses merely a depending I er peripheries of the refill bottom and top plates 22 and 23, with the upper section 01' such plates imperforate as in the case of skirt 35, while the lower portion of such cylinder would be perforated.

It will be noted that a space 38 is provided between the outer periphery of the filter cylinder 25A and the inside 01 the skirt 35 or imperforate' section of a casing or cylinder. By providing this space, the filtering capacity of that portion of the filter lying within the skirt is not lost, and would be used both in the case 01 inside-outside or outside-inside filtration.

While the use of a skirt or casing such as shown in Figure 3 is primarily designed and is preferable for an inside-outside flow, such a skirt or casing might also be used, if desired, with an outside-inside flow in the event that protection or a guide is desired for the exterior of the cylinder 25. In such event, however, it will be appreciated that the inner oil seal 29, such as shown in Figures 1 and 2, would be necessary, and the outer oil seal 29A might be omitted. I1 seal 29A were retained, it would be necessary to expose the refill top plate 23A or in some other suitable manner.

Obviously many variations may be made in the specific details of construction, and in the manner of operation, but the foregoing is -believed to illustrate the basic idea of this invention.

I claim:

1. In a fluid filter device, a filter cartridge comprising a tube, a disc-like plate secured to each end of the tube, a third disc-like plate intermediate the end plates slidable upon the tube in a fluid tight fit, a cylindrical mass of filtering material intermediate one of the end plates and the slidable plate, tension means tending to urge the floating plate against the cylinder, the inner periphery of said filter mass being spaced from the tube, and a hole in the tube located adjacent the end plate engaged by the filter mass.

2. In a fluid filter device, a mass of filtering material, a channel extending through the mass, a plate substantially co-extensive with one end of the mass perpendicular to the channel, a skirt extending from the plate encasing at least a part of the mass but spaced therefrom, a plate in a fluid ready flow 01' oil to the exterior against the adjacent end of ported by said the skirt in a fluid tight fit therewith and bearing the mass during expansion and contraction of the mass.

3. In a fluid filter device, an aperturedltube, a plate fixedly mountedat one end of the tube, a second plate fixedly mounted at the other end of the tube, a skirt extending from the first plate toward the second plate, a plate slidable in a fluid tight fit within the skirt, an aperture in the slidable plate larger than the exterior of the tube, and a mass of filter material surrounding but spaced from the tube, said mass being engaged in a fluid tight fit by the slidable plate and the second mentioned plate.

4. In a fluid filter device, a casing, an inlet port and an outlet port, a tube mounted in the casing in communication with one port, a plate mountedupon the tube, a filter cartridge supplate and spaced from the tube. gasket means at each end of the filter cartridge, a second plate engaging the gasket means at the opposite end of the cartridge to maintain the cartridge fixed with respect to the tube, an aperture in the tube intermediate the plates, said cartridge comprising a center tube, end plates fixedly mounted upon each end of the center tube in fluid tight flt therewith, a third plate intermediate the two fixed end plates slidable upon the center tube in a fluid tight fit and normally resting against one of the fixed end plates, a mass of filtering media surrounding but spaced from the center tube, one end of said mass resting upon one of said end plates, the opposite end of said mass bearing against the slidable plate, said slidable plate movable away from its adjacent end plate upon contraction of the filtering mass to .constantly maintain fluid tight engagement with the proximate end of the mass of filter medium.

5. In a filter device, a center tube, a plate secured in a fluid tight connection to each end of the tube, a filter mass surrounding the tube having one end adjoining one of the fixed plates, a plate slidable on the center tube and in fluid tight engagement with the center tube adjacent the other end of the filter mass, and resilient means under tension attached to the center tube and slidable plate urging said slidable plate against the filter mass.

6. A filter comprising a casing having an inlet port and an outlet port, a conduit communicating with one of said ports extending through the supported on said flange,

casing, closing means at the end of the conduit remote from the port communicating therewith preventing flow of the fluid to be filtered through the remote end, a flange rigidly attached to the conduit with a fluid tight fit, a filter cartridge said cartridge comprising a tube, a plate rigidly attached to the tube at each of its ends, a filter mass resting on one of said plates, a third plate normally adjacent the other or said fixed plates slidable upon said tube in a fluid tight fit and intermediate the fixed plates, said slidable plate bearing against the filter mass at all times in a fluid tight seal, a plate slidable upon the closing means preventing flow through the end of the conduit remote from the port communicating therewith, in a fluid tight fit, resilient means urging the plate slidable upon the closing means against the fixed plate remote from said flange to hold the filter cartridge firmly in place, and apertures in said conduit and center tube intermediate the ends of the filter mass to allow passage or the fluid being filtered.

SOUTHWICK W. BRIGGS.

REFERENCES CITED UNITED STATES PATENTS Number Name Date 730,485 Simoneton June 9, 1903 1,453,310 Engel, Sr. May 1, 1923 1,800,625 Hall et al Apr. 14, 1931 2,110,009 Weidenbacker Mar. 1, 1938 2,133,004 Williams et a1 Oct. 11, 1938 2,190,305 Auberschek Feb. '13, 1940 40 2,325,399 Houston July 27, 1943 2,339,703 Kamrath Jan. 18, 1944 2,345,848 Winslow et al Apr. 4, 1944 I FOREIGN PATENTS Number Country Date 597,003 France "2-- Aug. 21, 1925 608,587 France Apr. 24, 1926 730,485 France June 9, 1903 

